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How fast internet connection...

Posted on 2007-07-20
Medium Priority
Last Modified: 2013-12-14
If I want to run a public mailserver with about 200 users, how bog should my internet leased line be?
I know it is a relative question like "how long is a piece of string", but are there ant rules-of-thumb? ANy minimum requirements per x amount of users.

If all you are going to answer is "it depends......" then don't, I am looking for general thoughts and guidelines...
Question by:somewhereinafrica
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LVL 63

Expert Comment

ID: 19533540
Is your site graphics heavy ? Do you have Flash media on it ?

If it is not heavy with graphics, and fairly static then I would go with a 256 or 512K line.

Test it with a modem at different speeds and see how well it works and then multiply by 200 if it is OK

I hope this helps !
LVL 31

Expert Comment

ID: 19533756
How do you intend to run the Mailserver. Do you expect users to simply store the mail and retrieve via POP/IMAP or do you want to give full Webmail access via HTML GUI?

How often do you expect your users to go online?

I suppose as you don't want to restrict concurent connections you should work with the theoretical maximum as suggested by SysExpert and make a mathematical assesment.

All down to the nature of the mailservices provided....


Author Comment

ID: 19534025
Ok guys, I don;t want to be rude, but as I asked above; I don;t really know, at this stage it is theoretical. Give me some rules of thumb.

Ifi got 1mbit, how many "average" users would that support?
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LVL 31

Expert Comment

ID: 19534732

Respectfully, if we ask you questions to narrow down a possible solution, the we do this for a reason. As we take time out of our lifes to help others we want to make sure that any solution we give is adequate for the needs of the asker.

if you want an adequate answer you engage in the process. If you don't than you may as well ask the man in the street.

I will gracefully bow out.
LVL 63

Assisted Solution

SysExpert earned 375 total points
ID: 19535115
If your total is only 200 users ( not 200 simultaneous users ), then 512 K or 1 Mbps should suffice, unless

1) They are all on, all the time

2) They are doing heave duty attachments in mail ( 2-10 MByte attachments )

I hope this helps !

Author Comment

ID: 19535345
captainreiss - The 'problem' with technical people is that they always need data and variables. Sometimes that data does not exist. As in this case, I am working on a theortical setup and was looking for some general guidelines.
Again with respect - But i did mention in my question politely that if you were going to ask for variables then this was not what i was looking for (because I don't know them).

I can do the math: X users with Y amount if data accessed at Z frequency.... But what I was asking for was general rules of thumb, some real life experience - not a math equation. Again I explain this politely in my reply that I don't know the variables, and yet you get annoyed?

No, I don't want to ask the man in the street, that's why i paid allot of money to get quick answers here, where I as a paying customer have the right to choose the answers that helps me. I aprechiate your effort and I'm sorry that you feel that you have to 'bow out', you were just walking down a path that was not helping me, my intention was not to be rude.

SysExpert - would you say that 1 Mbps is sufficent or minimum? what size are you using right now on what user base?
LVL 97

Assisted Solution

by:Lee W, MVP
Lee W, MVP earned 375 total points
ID: 19536231
I'm sorry but this is a bit on the ridiculous side.  I want a mail server for 200 users, but I know nothing about them.  Don't give me answers if you're not going to be specific...

Are your users going to be getting SPAM?  Are they going to get large attachments frequently?  Roughly how many messages per day from the outside?  What's the point in asking if you don't even know these variables?  You need to provide SOME data... 200 users is like asking how much gas do I need to get from point A to point B but failing to indicate if you'll be taking a motorcycle or diesel train.  The answer is "you need some"

You want a sample?  Fine:
Lets say the user gets 10 e-mails an hour.  1 with a large attachment (1 MB), 6 in HTML format (25K each), and 3 plain text (3K Each).   That's 1159 K/hour per user.  Double that for messages the users send as well.  Multiply that by 200 users and you get 463.6 MB/hour needed bandwidth - assuming you don't use any web browsing or utilize the internet connection for anything else.  To download 231.8 MB in 1 hour, you'll need about a 128K line to accommodate that traffic using the line 100%.  DO ANYTHING ELSE (like web browsing, VoIP, FTP) or have one user need to send or receive larger files more frequently and this could throw everything off.  If your and office sending images to clients (like one of my clients), then this is too little.  If your a company that does nothing but the occasional e-mail, dialup is fine.

But really, if you want an estimate, think more about what you're doing and then provide more details.

Author Comment

ID: 19537564
Yes I want a mail server, and no I don't know anything about the usage picture, what is ridiculous about that?

Doing consultancy inside of USA must be very different from the theaters I work in (Africa, Asia). I get asked ALL THE TIME about theoretical questions with little meat on the bones to guide me, is that really that hard to imagine?

The usage picture in Post Conflict zones, and on-going war zones are extremely difficult to estimate. And I have to include Electricity availability, rats, corruption, rains, sand storms, theft, Extreme heat & dust and did I forget to mention armed attacks? This makes estimating very very difficult, I have no idea on how much the ministry of health is going to use their email, 2 years ago they were called rebels and were out in the bush killing each other!

I dont have any benchmarks on the usage of Sudanese politicians, Indian/Nepalese UN soldiers and AU-soldiers from Uganda and Rwandas to estimate from. UN floods the camps with people from all of the 180-something UN countries, so I have French, Spanish, Indonesian, Japanese , Russian, Swedish and American business users, do you have any average user statistics for these people to hand me?

Let me tell you all the details I know then; to paint a picture:
A worker camp is being built in Southern Sudan; this camp will house NGO workers and UN people, UN & AU soldiers, local, Ugandan, Kenyan and Chadian politicians and have a small business center. The guy who is building this is thinking of hosting an Exchange server in this hotel/camp.

Now the question remains, what kind of bandwidth would this guy need to server approx 200 users of the flavors mentioned above?

Your example (LEEW) was excellent, so was the theory of  SysExpert, somehow both of you succeeded in helping me with some basic theoretical reasoning that has helped me without knowing more than the very limited specs I gave you.

Im sorry to be so wordy about this, but I am so tired of people that seems unable to think outside the box. Not everything is as easy, available and logical as in the US (or whatever other western country you happen to be in). Sometimes I have to work blindfolded and with one hand tied behind my back because my client is some ex-bush-soldier who just stroke money from selling land and now wants to get computerized.

When you have drawn a power cable from an Armored Personnel  Carrier to hotwire a server to save data because a grenade has blown up the generator during a rebel attack, then you can come and complain to me that I dont have all the variables. Or rather then you would understand that not always you can get what you want, sometimes you have to use the force and go on theory& I am not out to piss anyone of, but before start complaining, calling me ridiculous, and getting so annoyed that you have to bow out just think about that sometimes, just sometimes the situation is different than the one you are living.

LVL 31

Accepted Solution

captain earned 750 total points
ID: 19538020
Hi somewhereinafrica:

You do a difficult job in a difficult environment, which is quite a task, one that we probably have not done or cannot even imagine. Maybe that is the point, we don't know about your frustration, for all we know you could be sitting in a small office in a comfortable environment. You don't and you have explained your frustration adequately. But you also need to consider for yourself how easy it is to rely on information you take for granted.

Points to consider:
You know your circumstances we don't.
We provide consultancy for free, whilst you pay for it, you don't pay us.  We work for free and try to support, provide question and take the odd abuse, again for free. That's why I bow out if I don't like the way a comment is responded to, not because I am annoyed, but as it is my choice what to do with my free time. I let you know o that fact, you don't ned to comment on it, other experts will step in.

If you would have expanded in a similar fashion earlier on to give us a glimpse of what your involved in, we could have given you advice in the light of the situation. In the end this is an exchange of expertise in a community spirit where expert help in their own time, and this deserves respect from both sides for it to work.

I don't have demoscopic statistics on your user group, but the consideration need to be:
If you only have mailusers pulling mail on local machines periodically then you could opt for a 512kb line and be fine, I think you may see some delay during peak times or if larger attachments are downloaded simmultaneously. In a mixed demoscopic rather than corporate environment you will have slower takeup, so after a while you may decide opening up for 1Mb.

We run 50 internal user with web and ftp outbound and 15 remote users with Lotus Notes mail replication plus an open FTP for our customers to upload graphic files on a 2Mb and have not experienced any lag ever. Again you will need to think of who else shares the line from 'the other side', ie do you have users on the mailserver side that may need to share the bandwidth?

the type of connection depends on what is on offer, here in the UK SDSL connections are considerably cheaper than tiered solutions, but you get less uptime and contention rates of up to 20 ( that is 20 users up to the exchange, effectively causing fluctuation of your real speed). I suggest tier over SDSL if you opt for the 512kb, and obviously if that is available to you.

I wish you every success in getting this implementedand have the utmost respect for what you are doing, but hope that you can, even if just for a moment see our side. We are here to help, it is just that most of the time, if not almost all the time the situation is different than the one you are living.

best wishes


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